Patent Literature 1 listed hereinbelow discloses an example of a conventional warm working method for a stainless steel foil of this type. Thus, Patent Literature 1 describes cooling a punch to 0° C. to 30° C. and heating a pressure pad to 60° C. to 150° C. when drawing an austenitic stainless steel sheet with a thickness of about 800 μm to 1000 μm.    Patent Literature 1: Japanese Patent Application Publication No. 2009-113058.